Intel 8257x Ethernet boards have a feature called Serial Over Lan.
This feature works by emulating a serial port, and it is detected by
kernel as a normal 8250 port. However, this emulation is not perfect, as
also noticed on changeset 7500b1f602.
Before this patch, the kernel were trying to check if the serial TX is
capable of work using IRQ's.
This were done with a code similar this:
serial_outp(up, UART_IER, UART_IER_THRI);
lsr = serial_in(up, UART_LSR);
iir = serial_in(up, UART_IIR);
serial_outp(up, UART_IER, 0);
if (lsr & UART_LSR_TEMT && iir & UART_IIR_NO_INT)
up->bugs |= UART_BUG_TXEN;
This works fine for other 8250 ports, but, on 8250-emulated SoL port, the
chip is a little lazy to down UART_IIR_NO_INT at UART_IIR register.
Due to that, UART_BUG_TXEN is sometimes enabled. However, as TX IRQ keeps
working, and the TX polling is now enabled, the driver miss-interprets the
IRQ received later, hanging up the machine until a key is pressed at the
serial console.
This is the 6 version of this patch. Previous versions were trying to
introduce a large enough delay between serial_outp and serial_in(up,
UART_IIR), but not taking forever. However, the needed delay couldn't be
safely determined.
At the experimental tests, a delay of 1us solves most of the cases, but
still hangs sometimes. Increasing the delay to 5us was better, but still
doesn't solve. A very high delay of 50 ms seemed to work every time.
However, poking around with delays and pray for it to be enough doesn't
seem to be a good approach, even for a quirk.
So, instead of playing with random large arbitrary delays, let's just
disable UART_BUG_TXEN for all SoL ports.
[akpm@linux-foundation.org: fix warnings]
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit b430428a18 ("8250: Don't clobber
spinlocks.") introduced a regression on the parisc architecture, which
broke the handover to the serial port at boottime.
early_serial_setup() was changed to only copy a subset of the uart_port
fields, and sadly the "type" and "line" fields were forgotten and thus
the serial port was not initialized and could not be used for a
handover. This patch fixes this by copying the missing fields.
As this change to early_serial_setup() doesn't need an initialized
spinlock in the uart_port struct any longer, we can drop the spinlock
initialization in the superio driver.
Cc: David Daney <ddaney@caviumnetworks.com>
Cc: Tomaso Paoletti <tpaoletti@caviumnetworks.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Acked-by: Kyle McMartin <kyle@mcmartin.ca>
Cc: linux-parisc@vger.kernel.org
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit d87a6d9 ("drivers/serial/: remove CVS keywords") removed one
space too many in the printk in serial8250_init(). Put it back in (and
add a comma for clarity).
Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Cavium UART implementation is not covered by existing uart_configS.
Define a new uart_config (PORT_OCTEON) which is specified by OCTEON
platform device registration code.
Signed-off-by: Tomaso Paoletti <tpaoletti@caviumnetworks.com>
Signed-off-by: David Daney <ddaney@caviumnetworks.com>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add flag value UPF_FIXED_TYPE which specifies that the UART type is
known and should not be probed. For this case the UARTs properties
are just copied out of the uart_config entry.
This allows us to keep SOC specific 8250 probe code out of 8250.c. In
this case we know the serial hardware will not be changing as it is on
the same silicon as the CPU, and we can specify it with certainty in
the board/cpu setup code.
The alternative is to load up 8250.c with a bunch of OCTEON specific
special cases in the probing code.
Signed-off-by: David Daney <ddaney@caviumnetworks.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In order to use Cavium OCTEON specific serial i/o drivers, we first
patch the 8250 driver to use replaceable I/O functions. Compatible
I/O functions are added for existing iotypeS.
An added benefit of this change is that it makes it easy to factor
some of the existing special cases out to board/SOC specific support
code.
The alternative is to load up 8250.c with a bunch of OCTEON specific
iotype code and bug work-arounds.
Signed-off-by: David Daney <ddaney@caviumnetworks.com>
Signed-off-by: Tomaso Paoletti <tpaoletti@caviumnetworks.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In serial8250_isa_init_ports(), the port's lock is initialized. We
should not overwrite it. In early_serial_setup(), only copy in the
fields we need. Since the early console code only uses a subset of
the fields, these are sufficient.
Signed-off-by: David Daney <ddaney@caviumnetworks.com>
Signed-off-by: Tomaso Paoletti <tpaoletti@caviumnetworks.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This merges branches irq/genirq, irq/sparseirq-v4, timers/hpet-percpu
and x86/uv.
The sparseirq branch is just preliminary groundwork: no sparse IRQs are
actually implemented by this tree anymore - just the new APIs are added
while keeping the old way intact as well (the new APIs map 1:1 to
irq_desc[]). The 'real' sparse IRQ support will then be a relatively
small patch ontop of this - with a v2.6.29 merge target.
* 'genirq-v28-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (178 commits)
genirq: improve include files
intr_remapping: fix typo
io_apic: make irq_mis_count available on 64-bit too
genirq: fix name space collisions of nr_irqs in arch/*
genirq: fix name space collision of nr_irqs in autoprobe.c
genirq: use iterators for irq_desc loops
proc: fixup irq iterator
genirq: add reverse iterator for irq_desc
x86: move ack_bad_irq() to irq.c
x86: unify show_interrupts() and proc helpers
x86: cleanup show_interrupts
genirq: cleanup the sparseirq modifications
genirq: remove artifacts from sparseirq removal
genirq: revert dynarray
genirq: remove irq_to_desc_alloc
genirq: remove sparse irq code
genirq: use inline function for irq_to_desc
genirq: consolidate nr_irqs and for_each_irq_desc()
x86: remove sparse irq from Kconfig
genirq: define nr_irqs for architectures with GENERIC_HARDIRQS=n
...
Splitting the 8250 code back up to avoid a clash with the NR_IRQS removal
patch introduced a last minute bug. Put back the additional needed lines
for the old lock init
Signed-off-by: Alan Cox <alan@redhat.com>
[ Ingo also reports that this can cause a spontaneous reboot crash with
certain configs, and sends in an identical patch ]
Tested-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The multiple drivers share the minor space occupied by a particular major
number, the actual index within the device name's space is indicated by
the tty_driver->name_base + uart_port->line
Another usable formula is (uart_driver->minor - MINOR_BASE) + port->line
Use those to print the device names properly in such situations in
serial_core.c and 8250.c
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This requires three changes:
1) Remove !SPARC restriction in Kconfig.
2) Move Sparc specific serial drivers before 8250, so that serial
console devices don't change names on us, even if 8250 finds
devices.
3) Since the Sparc specific serial drivers try to use the
same major/minor device namespace as 8250, some coordination
is necessary. Use the sunserial_*() layer routines to allocate
minor number space within TTY_MAJOR when CONFIG_SPARC.
This has no effect on other platforms.
Thanks to Josip Rodin for bringing up this issue and testing
plus debugging various revisions of this patch.
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Remove some inlines from various functions that are called once, are too
big to inline, or are called only from slow path code. This saves around
300 bytes of code for me.
Signed-off-by: Will Newton <will.newton@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A function to contain common code for the size of the resource we
need to allocate or free. OMAP ports need 22 bytes rather than
the standard 8 bytes.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Make is_omap_port() take the uart_8250_port structure so it can do
whatever test it desires. Convert the test to compare the physical
addresses rather than virtual addresses.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Recent changes to tighten the check for UARTs that don't correctly
re-assert THRE (01c194d927: "serial 8250:
tighten test for using backup timer") caused problems when such a UART was
opened for the second time - the bug could only successfully be detected
at first initialization. For users of this version of this particular
UART IP it is fatal.
This patch stores the information about the bug in the bugs field of the
port structure when the port is first started up so subsequent opens can
check this bit even if the test for the bug fails.
David Brownell: "My own exposure to this is that the UART on DaVinci
hardware, which TI allegedly derived from its original 16550 logic, has
periodically gone from working to unusable with the mainline 8250.c ...
and back and forth a bunch. Currently it's "unusable", a regression from
some previous versions. With this patch from Will, it's usable."
Signed-off-by: Will Newton <will.newton@gmail.com>
Acked-by: Alex Williamson <alex.williamson@hp.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: David Brownell <david-b@pacbell.net>
Cc: <stable@kernel.org> [2.6.26.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
serial8250_startup() doesn't disable interrupts while taking the &up->port.lock
which might race against the interrupt handler serial8250_interrupt(), which
when entered, will deadlock waiting for the lock to be released.
Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
Tested-by: Ingo Molnar <mingo@elte.hu>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Intel 82571 has a "Serial Over LAN" feature that doesn't properly
implements the receiving of break characters. When a break is received,
it doesn't set UART_LSR_DR and unless another character is received, the
break won't be received by the application.
Signed-off-by: Aristeu Rozanski <arozansk@redhat.com>
Acked-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
With SMP kernels _irqsave spinlock disables only local interrupts, while
the shared serial interrupt could be assigned to the CPU that is not
currently starting up the serial port.
This might cause issues because serial8250_startup() routine issues
IRQ-triggering operations before registering the port in the IRQ chain
(though, this is fine to do and done explicitly because we don't want to
process any interrupts on the port startup).
With RT kernels and preemptable hardirqs, _irqsave spinlock does not
disable local hardirqs, and the bug could be reproduced much easily:
$ cat /dev/ttyS0 &
$ cat /dev/ttyS1
irq 42: nobody cared (try booting with the "irqpoll" option)
Call Trace:
[C0475EB0] [C0008A98] show_stack+0x4c/0x1ac (unreliable)
[C0475EF0] [C004BBD4] __report_bad_irq+0x34/0xb8
[C0475F10] [C004BD38] note_interrupt+0xe0/0x308
[C0475F50] [C004B09C] thread_simple_irq+0xdc/0x104
[C0475F70] [C004B3FC] do_irqd+0x338/0x3c8
[C0475FC0] [C00398E0] kthread+0xf8/0x100
[C0475FF0] [C0011FE0] original_kernel_thread+0x44/0x60
handlers:
[<c02112c4>] (serial8250_interrupt+0x0/0x138)
Disabling IRQ #42
After this, all serial ports on the given IRQ are non-functional.
To fix the issue we should explicitly disable shared IRQ before
issuing any IRQ-triggering operations.
I also changed spin_lock_irqsave to the ordinary spin_lock, since it
seems to be safe: chain does not contain new port (yet), thus nobody
will interfere us from the ISRs.
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Switch the serial_core based drivers to use the new tty_port structure.
We can't quite use all of it yet because of the dynamically allocated
extras in the serial_core layer.
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch removes CVS keywords that weren't updated for a long time in
comments, printk's and MODULE_DESCRIPTION's (no printk's or
MODULE_DESCRIPTION's are completely removed).
While doing this I also found and fixed a missing \n in a printk
in m32r_sio.c
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
I had 8250.nr_uarts=16 in the boot line of a test kernel and I had a weird
mysterious crash in sysfs. After taking an in-depth look I realized that
CONFIG_SERIAL_8250_NR_UARTS was set to 4 and I was walking off the end of
the serial8250_ports array.
Ouch!!!
Don't let this happen to someone else.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: Alan Cox <alan@redhat.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
As Russell pointed out, original patch will break some serial configurations
because of the dependency of the <asm/serial.h> header file.
Revert it first and try to find out other solution later
Cc: Javier Herrero <jherrero@hvsistemas.es>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Russell King <rmk+lkml@arm.linux.org.uk>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
Added support for 8250-class UARTs in HV Sistemas H8606 board,
modification in 8250.c driver for correct compilation with Blackfin
Besides, I think that there is more people using 8250-class UARTs
with a different hardware than the H8606 board. This code can be shared
by them.
Signed-off-by: Javier Herrero <jherrero@hvsistemas.es>
Acked-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
Signed-off-by: Alan Cox <alan@redhat.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Thomas Koeller had reported an issue where a device that had been making use
of the UART_BUG_TXEN code in the 8250 driver was mistakenly being caught by
the backup timer test, causing the device to work improperly.
To fix this, tighten the test requirements to enable the backup timer
workaround.
The backup timer is really meant to catch UARTs that don't re-assert the THRE
interrupt. The expectation is that they do initially assert THRE. This patch
clarifies the test.
Signed-off-by: Alex Williamson <alex.williamson@hp.com>
Cc: Thomas Koeller <thomas@koeller.dyndns.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We try and write the correct speed back but the serial midlayer already
mangles the speed on us and that means if we request B0 we report back B9600
when we should not. For now we'll hack around this in the drivers and serial
code, pending a better long term solution.
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
polled console handling support, to access a console in an irq-less
way while in debug or irq context.
absolutely zero impact as long as CONFIG_CONSOLE_POLL is disabled.
(which is the default)
[ jan.kiszka@siemens.com: lots of cleanups ]
[ mingo@elte.hu: redesign, splitups, cleanups. ]
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Jan Kiszka <jan.kiszka@web.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Allow the private_data field to be specified in platform_data for the
standard 8250/16550 UART. This field is used by DW APB type UARTs and
without this patch it's only possible to set this field when registering
the port by hand. If private_data is not set then the driver will
potentially oops with a NULL pointer dereference.
Signed-off-by: Will Newton <will.newton@gmail.com>
Acked-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Reading the LSR clears the break, parity, frame error, and overrun bits in
the 8250 chip, but these are not being saved in all places that read the
LSR. Same goes for the MSR delta bits. Save the LSR bits off whenever the
lsr is read so they can be handled later in the receive routine. Save the
MSR bits to be handled in the modem status routine.
Also, clear the stored bits and clear the interrupt registers before
enabling interrupts, to avoid handling old values of the stored bits in the
interrupt routines.
[akpm@linux-foundation.org: clean up pre-existing code]
Signed-off-by: Corey Minyard <minyard@acm.org>
Cc: Russell King <rmk+lkml@arm.linux.org.uk>
Cc: Yinghai Lu <yinghai.lu@sun.com>
Cc: Bjorn Helgaas <bjorn.helgaas@hp.com>
Acked-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
the early setup function serial8250_console_early_setup() can be called
from non __init code (eg. hotpluggable serial ports like serial_cs) so
remove the __init from the call chain to avoid crashes.
Signed-off-by: Daniel Ritz <daniel.ritz@gmx.ch>
Cc: Yinghai Lu <yinghai.lu@sun.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
At present, various parts of the serial code use unsigned long to define
resource addresses. This is a problem, because some 32-bit platforms have
physical addresses larger than 32-bits, and have mmio serial uarts located
above the 4GB point.
This patch changes the type of mapbase in both struct uart_port and struct
plat_serial8250_port to resource_size_t, which can be configured to be 64
bits on such platforms. The mapbase in serial_struct can't safely be
changed, because that structure is user visible.
Signed-off-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Beacuse SERIAL_PORT_DFNS is removed from include/asm-i386/serial.h and
include/asm-x86_64/serial.h. the serial8250_ports need to be probed late in
serial initializing stage. the console_init=>serial8250_console_init=>
register_console=>serial8250_console_setup will return -ENDEV, and console
ttyS0 can not be enabled at that time. need to wait till uart_add_one_port in
drivers/serial/serial_core.c to call register_console to get console ttyS0.
that is too late.
Make early_uart to use early_param, so uart console can be used earlier. Make
it to be bootconsole with CON_BOOT flag, so can use console handover feature.
and it will switch to corresponding normal serial console automatically.
new command line will be:
console=uart8250,io,0x3f8,9600n8
console=uart8250,mmio,0xff5e0000,115200n8
or
earlycon=uart8250,io,0x3f8,9600n8
earlycon=uart8250,mmio,0xff5e0000,115200n8
it will print in very early stage:
Early serial console at I/O port 0x3f8 (options '9600n8')
console [uart0] enabled
later for console it will print:
console handover: boot [uart0] -> real [ttyS0]
Signed-off-by: <yinghai.lu@sun.com>
Cc: Andi Kleen <ak@suse.de>
Cc: Bjorn Helgaas <bjorn.helgaas@hp.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Gerd Hoffmann <kraxel@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
After a suspend/resume cycle, the UART may have been reset into
low-speed mode -- either because it's actually been reset, or because
the firmware pokes at the old-style divisor registers. If we detected it
as a NS16550A SuperIO chip in the first place and set baud_base to
921600, then we should do so again in the resume path.
This patch adds that code to serial8250_resume_port(), and also makes
serial8250_resume() actually call serial8250_resume_port() for each port
instead of just calling uart_resume_port() directly. And thus fixes
serial port operation after suspend/resume.
It also fixes a bogus comment where we write the EXCR2 register with a
comment saying /* EXCR1 */
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Acked-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Remove some obviously old interrupt disable/enable code that has been
commented out.
Signed-off-by: Josh Boyer <jwboyer@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add support for the integrated serial ports of the MIPS RM9122 processor
and its relatives.
The patch also does some whitespace cleanup.
[akpm@linux-foundation.org: cleanups]
Signed-off-by: Thomas Koeller <thomas.koeller@baslerweb.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Serial driver patch for the PMC-Sierra MSP71xx devices.
There are three different fixes:
1 Fix for DesignWare APB THRE errata: In brief, this is a non-standard
16550 in that the THRE interrupt will not re-assert itself simply by
disabling and re-enabling the THRI bit in the IER, it is only re-enabled
if a character is actually sent out.
It appears that the "8250-uart-backup-timer.patch" in the "mm" tree
also fixes it so we have dropped our initial workaround. This patch now
needs to be applied on top of that "mm" patch.
2 Fix for Busy Detect on LCR write: The DesignWare APB UART has a feature
which causes a new Busy Detect interrupt to be generated if it's busy
when the LCR is written. This fix saves the value of the LCR and
rewrites it after clearing the interrupt.
3 Workaround for interrupt/data concurrency issue: The SoC needs to
ensure that writes that can cause interrupts to be cleared reach the UART
before returning from the ISR. This fix reads a non-destructive register
on the UART so the read transaction completion ensures the previously
queued write transaction has also completed.
Signed-off-by: Marc St-Jean <Marc_St-Jean@pmc-sierra.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 40b36daa introduced possibility that serial8250_backup_timeout() ->
serial8250_handle_port() locks port.lock without disabling irqs, thus
allowing deadlock against interrupt handler (port.lock is acquired in
serial8250_interrupt()).
Spotted by lockdep.
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Cc: Dave Jones <davej@codemonkey.org.uk>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Alex Williamson <alex.williamson@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
I encountered the following kernel panic. The cause of this problem was
NULL pointer access in check_modem_status() in 8250.c. I confirmed this
problem is fixed by the attached patch, but I don't know this is the
correct fix.
sadc[4378]: NaT consumption 2216203124768 [1]
Modules linked in: binfmt_misc dm_mirror dm_mod thermal processor fan
container button sg e100 eepro100 mii ehci_hcd ohci_hcd
Pid: 4378, CPU 0, comm: sadc
psr : 00001210085a2010 ifs : 8000000000000289 ip : [<a000000100482071>]
Not tainted
ip is at check_modem_status+0xf1/0x360
Call Trace:
[<a000000100013940>] show_stack+0x40/0xa0
[<a0000001000145a0>] show_regs+0x840/0x880
[<a0000001000368e0>] die+0x1c0/0x2c0
[<a000000100036a30>] die_if_kernel+0x50/0x80
[<a000000100037c40>] ia64_fault+0x11e0/0x1300
[<a00000010000bdc0>] ia64_leave_kernel+0x0/0x280
[<a000000100482070>] check_modem_status+0xf0/0x360
[<a000000100482300>] serial8250_get_mctrl+0x20/0xa0
[<a000000100478170>] uart_read_proc+0x250/0x860
[<a0000001001c16d0>] proc_file_read+0x1d0/0x4c0
[<a0000001001394b0>] vfs_read+0x1b0/0x300
[<a000000100139cd0>] sys_read+0x70/0xe0
[<a00000010000bc20>] ia64_ret_from_syscall+0x0/0x20
[<a000000000010620>] __kernel_syscall_via_break+0x0/0x20
Fix the possible NULL pointer access in check_modem_status() in 8250.c. The
check_modem_status() would access 'info' member of uart_port structure, but it
is not initialized before uart_open() is called. The check_modem_status() can
be called through /proc/tty/driver/serial before uart_open() is called.
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Taku Izumi <izumi2005@soft.fujitsu.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The patch below works around a minor bug found in the UART of the remote
management card used in many HP ia64 and parisc servers (aka the Diva
UARTs). The problem is that the UART does not reassert the THRE interrupt
if it has been previously cleared and the IIR THRI bit is re-enabled. This
can produce a very annoying failure mode when used as a serial console,
allowing a boot/reboot to hang indefinitely until an RX interrupt kicks it
into working again (ie. an unattended reboot could stall).
To solve this problem, a backup timer is introduced that runs alongside the
standard interrupt driven mechanism. This timer wakes up periodically,
checks for a hang condition and gets characters moving again. This backup
mechanism is only enabled if the UART is detected as having this problem,
so systems without these UARTs will have no additional overhead.
This version of the patch incorporates previous comments from Pavel and
removes races in the bug detection code. The test is now done before the
irq linking to prevent races with interrupt handler clearing the THRE
interrupt. Short delays and syncs are also added to ensure the device is
able to update register state before the result is tested.
Aristeu says:
this was tested on the following HP machines and solved the problem:
rx2600, rx2620, rx1600 and rx1620s.
hpa says:
I have seen this same bug in soft UART IP from "a major vendor."
Signed-off-by: Alex Williamson <alex.williamson@hp.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Acked-by: Aristeu Sergio Rozanski Filho <aris@cathedrallabs.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Get the Perle quad-modem PCI card (PCI-RAS4) detected by serial driver. It
may also get the PCI-RAS8 running, but can't guarantee as I didn't had one for
testing.
Signed-off-by: Thomas Hoehn <thomas.hoehn@avocent.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
o MODPOST generates warning for i386 if compiled with CONFIG_RELOCATABLE=y
and serial console support is enabled.
o Serial console setup function, serial8250_console_setup(), is a non __init
function and it calls functions which are of type __init().
(uart_parse_options() and uart_set_options()). Assuming, setup will
be called during init time, changing serial8250_console_setup() to __init.
o Adding one more pattern to modpost whitelist. Console drivers might
have *_console structures containing references to setup functions which
can be of __init type. Don't generate warnings for those.
WARNING: vmlinux - Section mismatch: reference to .init.text: from .data between 'serial8250_console' (at offset 0xc05a33d8) and 'serial8250_reg'
Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
This is the grungy swap all the occurrences in the right places patch that
goes with the updates. At this point we have the same functionality as
before (except that sgttyb() returns speeds not zero) and are ready to
begin turning new stuff on providing nobody reports lots of bugs
If you are a tty driver author converting an out of tree driver the only
impact should be termios->ktermios name changes for the speed/property
setting functions from your upper layers.
If you are implementing your own TCGETS function before then your driver
was broken already and its about to get a whole lot more painful for you so
please fix it 8)
Also fill in c_ispeed/ospeed on init for most devices, although the current
code will do this for you anyway but I'd like eventually to lose that extra
paranoia
[akpm@osdl.org: bluetooth fix]
[mp3@de.ibm.com: sclp fix]
[mp3@de.ibm.com: warning fix for tty3270]
[hugh@veritas.com: fix tty_ioctl powerpc build]
[jdike@addtoit.com: uml: fix ->set_termios declaration]
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Martin Peschke <mp3@de.ibm.com>
Acked-by: Peter Oberparleiter <oberpar@de.ibm.com>
Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
